Inside the gymnasium on Friday at Rainier Beach High School was a scene best described as organized chaos.

Sydney, 9, explains why her new app is so cool.

While DJ Midnight Mike blasted out today’s hottest tunes, a big group had formed a circle for an impromptu dance competition. Minutes later, a handful of nervous students took the microphone and spoke about their just-developed applications — some even walked away winning an Xbox One console or a Google Nexus tablet. During it all, several hundred others were heads down with their computer science 101 handbooks, trying to finish creating their own Flappy Bird games.

Who knew coding could be so cool.

The second-annual Puget Sound App Day saw more than 850 students from 54 schools around the state come together in South Seattle to learn basic development skills — and have a whole lot of fun in the process.

Prior to Friday, a majority of these kids had no previous exposure to computer science, a subject many students often label as only for the so-called geeks.

The goal of App Day, organized by Seattle Public Schools, Microsoft and a bevy of other supporters, is to change all that.

“It’s about the first experience,” said Microsoft Research developer Peli de Halleux, who created the event last year. “It’s realizing that you can do some coding and create your own apps. We want that first joyful experience.”

A dance competition … at a high school coding hackathon.

Not everybody walked out of the gym inspired to become the next Bill Gates. But it was clear that at least a few inspired kids came away with a sense of accomplishment and an interest in coding.

“This was really fun,” said 12-year-old Evan. “You can be creative and do what you want.”

“I learned how to make new games on different devices,” noted 9-year-old Sydney.

“You do lots of different things and create lots of stuff,” added 14-year-old Jack. “There are infinite possibilities.”

One neat aspect of Friday’s event is that most of the students learned the basics of computer science and built apps using devices they already use every day.

That’s made possible by Microsoft Research’s TouchDevelop platform, which allows you to easily build apps on the iPad, iPhone, Android, PC, Mac and Windows Phone. It runs on Internet Explorer, Chrome and Safari, while storing all the data in the Windows Azure cloud.

Students spent several hours on Friday using TouchDevelop to work through tutorials that taught them how to create drawings with turtles and build games similar to Flappy Bird. They were given trophies for specific achievements and would receive raffle tickets in exchange.

“Time will tell in terms of how many we managed to hook onto this thing,” de Halleux said. “But for all of those that brought their devices, they can go back onto the bus today and keep coding. It follows them because we managed to put coding straight into their devices.”

Given the recent interest in computer science education, it wasn’t all that surprising to see such a big turnout at App Day — especially programs like TouchDevelop and Code.org making it easier than ever for students to learn the basics of programming. There were even some parents who took their children out of class and brought them to Rainier Beach in order to participate on Friday.

“Our grand vision was to have some formula where we take kids that don’t have coding experience and get them exposed to it,” said Michael Braun, a lead organizer and computer science teacher at Rainier Beach. “Having a forum like this really allows them to both learn some basic skills, plus get mentorship.”

App Day students had the chance to win prizes like an Xbox One or Google Nexus.

Another notable part of App Day were the students themselves, many of whom come from low-income households.

“Once you get the concept of coding, it can really fuel you being a change agent,” Braun said. “You can affect your local community and solve problems that haven’t been addressed. These students, wherever they come from, all have local issues. Once they have the power and understand the tools to code, they can create software and programs that make a big change.”

Braun’s vision is ambitious, yet is one that’s made possible thanks to an event like App Day. But for now, at least, the children are equipped with an excuse to play on their devices even more.

“I heard the students today saying that they want to do this coding stuff because now Mom can’t take away their phone,” said Sam Stokes, an Academic Developer Evangelist for Microsoft. “They have a little more power.”

Taylor Soper is a GeekWire staff reporter who covers a wide variety of tech assignments, including emerging startups in Seattle and Portland, the sharing economy and the intersection of technology and sports. Follow him @taylor_soper and email taylor@geekwire.com.